Carotenoids are one of the groups of pigments most widely distributed in nature and they also have a variety of roles. Some of the main and best known among these are related to its critical role in the photokinetic response of plants, in phototropic response of fish and as of Vitamin A precursors in some mammals and birds.
Among the different types of known carotenoids are those that are oxygenated and are called xanthophylls as a group. Within this particular group are lutein [(3R,3′R,6′R)-β,ε-carotene-3,3′-diol] and zeaxantine [(3R,3′R)-β,β-carotene-3,3′-diol] Frequently, these pigments are found together and with a good degree of concentration in some plants like the Marigold (Tagetes erecta sp.) which has found in Peru suitable climatic and soil conditions to produce high quality and completely natural and organic flowers. Traditionally, marigold xanthophylls have found its main application in the pigmentation of chicken skin and eggs yolks.
Although, currently both lutein and zeaxantine have found an important and increasingly growing use as antioxidant and inmunostimulant for some species of animals as well as for human beings. Thus, their beneficial effects have been shown in the treatment of macular degeneration associated with age, various kinds of cancer and cardiovascular diseases, among others. Different mechanisms have been suggested to try to explain how carotenoids protect biological systems, among them the deactivation of electronically reactive species like singlet oxygen and the deactivation of chemically reactive species like peroxyl or alkoxyl radicals that are at times found in cells and thus start dangerous oxidation reactions.
Frequently, commercially available extracts of marigold contain other compounds in addition to the above-mentioned xanthophylls. For example, 1–3% of β-criptoxantine, 2–5% of β-carotene, and variable quantities of epoxide derivatives both lutein and zeaxantine. More often these can constitute from 5% to 20% of xanthophylls of the extract.
Epoxicarotenoids are widely distributed in nature and constitute the most part of carotenoids that human beings consume as part of their fruit and vegetable diets. In fact, epoxides like neoxantine, violaxantine (5,6,5′,6′-diepoxi-zeaxantine) and taraxantine (5,6-epoxi-lutein) are more plentiful than 5,6-epoxi-β-carotene.
More recently, it has been shown that some of these epoxides are not efficiently absorbed by humans (Barua, 2001).
Lutein and zeaxantine are naturally found as mono- and di-esters, mainly linked to fatty acids like palmitic, stearic, miristic, etc.
Other components of these extracts are various free fatty acids, waxes, phospholipids, gums, etc. An appropriate method for obtaining lutein and zeaxantine for human consumption should efficiently remove any component other than xanthophylls of interest.
Various processes for such end have been reported for many years. For example, Phillip (1977) obtained lutein esters directly purified from Marigold oleoresins, precipitating them with alcohol and further filtration. Khachik (1995) obtained free lutein crystals from saponified marigold and recrystallizing many halogenated solvents, alcohols, etc. Ausich (1997) recovered lutein by saponifying marigold oleoresins in propilenglicol and centrifugating the material obtained. Koch (1999) treated enzymatically chromoplasts containing carotenoids and then removed insolubles. The sediment obtained is alkalinized in alcohol to finally obtain a concentrate of carotenoids. Levy (2001) prepared a concentrate of lutein trans-esters by first treating marigold oleoresins with a hydrocarbon to obtain esters and then with alcohol to remove what he calls xanthophylls cis-esters. Khachik (2001) reported the method for obtaining lutein concentrates from marigold, by recrystallizing in THF and then washing it with alcohol. Rodriguez et al. (2001) described a method to remove chlorophyls and fats from mechanically reaped extracts of marigold to recover free lutein concentrates. Madhavi (2002) offered a procedure to obtain marigold carotenoides in high concentrations when oleoresins saponify in isopropanol and alkali to centrifuge the mixture obtained and recover lutein crystals.
In all cases, the quality of raw material seems irrelevant in the purification processes. However, concentrates obtained to date by different companies and in accordance with the studies reviewed, do not show a total absence of epoxicarotenoids or arbitrarily omit their presence because these components do not provide the benefits of lutein or zeaxantine and they are commercially obvious.
Agricola Barranca, S.A uses marigold petals of the highest quality coming from cultivation and processes that ensured the absence of theses components and others that could be harmful or of dubious utility for humans. This and the technology described here are used to remove completely those compounds other than lutein and zeaxantine that may be present in saponified marigold extracts.